Semiconductor storage device

Abstract

Bit lines ( 51 ) and word lines ( 50 ) nonparallel to one other are so arranged as to cross, and a magneto-resistance element ( 52 ) serving as the storage element is arranged between a bit line and a word line at their intersection. Numeral 106 represents an upper electrode. The magneto-resistance element comprises a free magnetic layer the magnetization direction of which changes with the direction of a current flowing through the bit line at the intersection. The free magnetic layer is located close to the top face of the magneto-resistance element. The distance from the free magnetic layer to the bit line is larger than that from the free magnetic layer to the word line. The width of the word line is smaller than that of the bit line. The bit lines and the word lines are arranged at their respective predetermined repetition pitches. The repetition pitches of the bit lines are larger than those of the word lines.

1 . A semiconductor storage device in which a wiring of a first system and a wiring of a second system nonparallel to each other are so arranged as to intersect, and a magneto-resistance element as a storage element is disposed in a portion corresponding to an intersecting portion between the wiring of the first system and the wiring of the second system, the magneto-resistance element comprising a free magnetic layer whose magnetization direction changes with a direction of a current flowing through the wiring of the first system of the intersecting portion, 
 wherein a distance from the free magnetic layer to the wiring of the first system is larger than that from the free magnetic layer to the wiring of the second system.    
     
     
         2 . The semiconductor storage device according to  claim 1 , wherein the magneto-resistance element is disposed between the wiring of the first system and the wiring of the second system.  
     
     
         3 . The semiconductor storage device according to  claim 1 , wherein the wiring of the second system is positioned between the magneto-resistance element and the wiring of the first system.  
     
     
         4 . The semiconductor storage device according to  claim 1 , wherein a width of the wiring of the second system is smaller than that of the wiring of the first system.  
     
     
         5 . The semiconductor storage device according to  claim 1 , wherein the free magnetic layer is positioned in the vicinity of one surface of the magneto-resistance element, and the wiring of the second system is disposed on a side facing the one surface of the magneto-resistance element.  
     
     
         6 . The semiconductor storage device according to  claim 1 , wherein the free magnetic layer is positioned in the vicinity of one surface of the magneto-resistance element, and the wiring of the second system is disposed on a side facing a surface opposite to the one surface of the magneto-resistance element.  
     
     
         7 . The semiconductor storage device according to  claim 1 , wherein the wiring of the first system and the wiring of the second system are arranged at predetermined repetition pitches, and the repetition pitch of the wiring of the first system is lager than that of the wiring of the second system.  
     
     
         8 . The semiconductor storage device according to  claim 1 , wherein the magneto-resistance element has a shape longer in one axis direction.  
     
     
         9 . The semiconductor storage device according to  claim 8 , wherein the magneto-resistance element has a shape longer in a direction of the wiring of the second system rather than a direction of the wiring of the first system.  
     
     
         10 . The semiconductor storage device according to  claim 1 , wherein the wiring of the first system is a bit line, and the wiring of the second system is a word line.  
     
     
         11 . The semiconductor storage device according to  claim 1 , wherein the wiring of the first system is a write bit line, the wiring of the second system is a word line, and a read bit line having the same direction as that of the wiring of the first system is disposed separately from the wiring of the first system and the wiring of the second system.  
     
     
         12 . The semiconductor storage device according to  claim 11 , further comprising: a bit line control circuit which executes a control in such a manner as to supply a current for writing to both the write bit line and the read bit line.  
     
     
         13 . The semiconductor storage device according to  claim 11 , wherein the read bit line is disposed on the same side as that of the write bit line with respect to the magneto-resistance element.  
     
     
         14 . The semiconductor storage device according to  claim 11 , wherein the read bit line is disposed on a side opposite to that of the write bit line with respect to the magneto-resistance element.  
     
     
         15 . The semiconductor storage device according to  claim 1 , wherein the magneto-resistance element is constituted of the free magnetic layer, a tunneling insulating layer, a pinned magnetic layer, and an antiferromagnetic layer stacked in this order.  
     
     
         16 . The semiconductor storage device according to  claim 1 , wherein the wiring of the first system is constituted of a plurality of layers constituting the wiring of the first system, and the distance from the free magnetic layer to the wiring of the first system is a distance from the free layer to a layer in which a current flows mainly in the layers corresponding the wiring of the first system.  
     
     
         17 . The semiconductor storage device according to  claim 1 , wherein the wiring of the second system is constituted of a plurality of layers constituting the wiring of the second system, and the distance from the free magnetic layer to the wiring of the second system is a distance from the free layer to a layer in which a current flows mainly in the layers corresponding the wiring of the second system.  
     
     
         18 . The semiconductor storage device according to  claim 1 , wherein the magneto-resistance element is connected in series to a resistance element having nonlinear characteristics.